California: Climate Considerations for Processing Tomatoes

Research models show that increases in overall temperatures in California will have a direct effect on how some crops are going to be produced in the future.  In one study looking at processing tomato production in the Central Valley, researchers found that changing temperatures will likely have a noticeable impact on the timing of the growing season. 
 
 “We looked at the data all the way starting from 1950, into the future by 2030-2040 and see how the time of maturity is changing,” said Tapan Pathak, who serves as cooperative extension specialist in climate adaptation in agriculture at the University of California Division of Agriculture and Resources and UC Merced. “What we saw is, in general the time from emergence to maturity, the timeframe for processing tomatoes in that region, is going to shrink down almost by two to three weeks.”

Objective of this study was to analyze growing season trend in top five processing tomato-producing counties in California through the use of growing degree-days model and historical and future climate scenarios generated from the general circulation model (GCM). Based on the findings, the models indicated a significant decrease in the number of days between transplanting and maturity, with an expected harvest 2–3 weeks earlier than normal under current conditions and cultivars. Results from this study could be utilized to make strategic decisions such as variety selection, planting and harvest dates, agricultural water management, and studying trends in pests and diseases due to shifts and lengthening of tomato growing season in the tomato production areas of California.

One aspect that was not evaluated in the study was how the change in the crops timeline for maturity will affect yield.  Pathak noted that would be a good focal point for future research.  “One thing we didn’t look in this research was how the shift in the growing season, the emergence to maturity and shrinking timeframe is going to have an impact on yields of tomatoes – that is one thing we haven’t studied yet”.
Another area of production which would be impacted by a shift in the production season would be seen further down the supply chain. “A lot of those processors they have their timeline for when they need the tomatoes for the processing and so when you have this shift in the phenology, that sort of alters the timeframe by when they mature and then are ready for the processors,” said Pathak.  “So, there’s a whole shift in the management that they might have to think about in the future.”